请问下面这段代码怎么对齐啊,居上居中居下都行,注意那个position:absolute的控件必须是absolute不能改啊.
<table border=1>
<tr valign=middle>
<td height="20" width=600 align="center" style="vertical-align: middle;" valign=middle>
<textarea id="callingISDN" style="overflow-x:hidden;overflow-y:auto"></textarea>
<input type="button" name="selectcode" style="font-size:11px" value="常用号码">
<input id="file_upload_btn" type="button" value="导入" style="position:absolute;font-size:11px;">
</td>
</tr>
</table>
<table border=1>
<tr valign=middle>
<td height="20" width=600 align="center" style="vertical-align: middle;" valign=middle>
<textarea id="callingISDN" style="overflow-x:hidden;overflow-y:auto"></textarea>
<input type="button" name="selectcode" style="font-size:11px" value="常用号码">
<input id="file_upload_btn" type="button" value="导入" style="position:absolute;font-size:11px;">
</td>
</tr>
</table>
<table border=1>
<tr valign=middle>
<td height="20" align="center" style="vertical-align: middle;" valign=middle>
<textarea id="callingISDN" style="overflow-x:hidden;overflow-y:auto"> </textarea>
</td>
<td style="vertical-align:top">
<input type="button" name="selectcode" style="font-size:11px" value="常用号码">
</td>
<td style="vertical-align:top">
<input id="file_upload_btn" type="button" value="导入" style="position:absolute;font-size:11px;">
</td>
</tr>
</table>
检测高度然后设置position的top怎么弄啊?注意有一个的位置是position:absolute啊,不好弄
<tr>
<td height="20" width=600 style="vertical-align: middle;">
<textarea id="callingISDN" style="overflow-x:hidden;overflow-y:auto"> </textarea>
<input type="button" name="selectcode" style="position:absolute;margin-top:14;font-size:11px;" value="常用号码">
<input id="file_upload_btn" type="button" value="导入" style="position:absolute;margin-top:14;margin-left:80;font-size:11px;">
</td>
</tr>
</table>
<tr>
<td height="20" width=600 style="vertical-align: middle;">
<textarea id="callingISDN" style="overflow-x:hidden;overflow-y:auto"> </textarea>
<input type="button" name="selectcode" style="position:absolute;margin-top:14;font-size:11px;" value="常用号码">
<input id="file_upload_btn" type="button" value="导入" style="position:absolute;margin-top:14;margin-left:80;font-size:11px;">
</td>
</tr>
</table>
<tr valign=middle>
<td height="20" width=600 align="center" style="vertical-align: middle;" valign=middle>
<div align="left"><textarea id="callingISDN" style="overflow-x:hidden;overflow-y:auto"> </textarea></div>
<div align="left"><input type="button" name="selectcode" style="font-size:11px" value="常用号码">
<input id="file_upload_btn" type="button" value="导入" style="position:absolute;font-size:11px;"></div>
</td>
</tr>
</table>